14
Common Problems and Potential Solution
Problem
Possible Causes
Possible Solutions
37880 cannot pull au-
tomobile A/C system
into a vacuum
Service valves on hoses not properly in-
stalled
Service ball valve seals are worn.
Hoses on unit are loose or leak.
Automobile A/C system has a leak.
Check valve seals and threads and replace if need-
ed.
Replace valve seals and Schrader core depressor.
Tighten or replace hoses on unit.
Find and repair leak in A/C system.
High side gauge
readings above nor-
mal
Restriction in A/C system or Schrader
core.
Service hose ball valve closed.
Incorrect charge amount entered in unit.
Check hose connection and fix restriction. Replace
Schrader core.
Open the valve.
Recover, check scale calibration, and recharge
system.
Refrigerant not being
transferred during
Tank Refill.
Valve on supply tank closed.
Ball valve on blue service hose closed or
hose is constricted.
Wrong hose installed on new refrigerant
tank.
Storage tank is full.
Open Valve.
Open valve or straighten hose.
Install blue service hose on refrigerant tank.
Close valve on new supply. Disconnect service
hose.
Touch Pad will not
accept commands
Key on touch pad is stuck.
Bad Touch Pad.
Wire disconnected between touch pad and
microprocessor.
Microprocessor malfunction.
Feel for non-responsive key. If not responding, call
Technical Support.
Call Technical Support.
Call Technical Support.
Call Technical Support.
Fan not running in any
cycle
Loose power wire to fan.
Microprocessor malfunction.
Fan malfunction.
Locate loose fitting and reconnect.
Call Technical Support.
Call Technical Support.
Machine will not turn
on
Power cord is not plugged into a 120 Volt
outlet.
Circuit breaker tripped on shop power
panel.
Bad Main Power switch.
Loose wire.
Bad Transformer on microprocessor
board.
Plug into outlet.
Reset circuit breaker. If circuit breaker immediately
trips, do not reset. Consult a qualified electrician.
Call Technical Support.
Repair loose wire.
Call Technical Support.
Unit will not recover
refrigerant from A/C
system
Valves on service hoses shut.
Service hose is constricted.
Unit storage tank valve is closed.
Open valves.
Straighten hose.
Open tank valves.
Compressor not operating.
Call Technical Support.
Unit will not charge
refrigerant into vehicle
Valves on service hoses shut
Service hose is constricted
Unit storage tank valve is closed
Open valves
Straighten hose
Open tank valves
Compressor not operating
Call Technical Support.
Refrigerant leaking
during charging
Service valves on hoses not properly in-
stalled on A/C system.
Check valve seals and threads and replace if need-
ed.
Service ball valve seals are worn.
Replace valve seals and Schrader core depressor
Hoses on unit are loose or leak.
Tighten or replace hoses on unit
Automobile A/C system has a leak
Find leak in A/C system and repair.
Troubleshooting Information
The 3788X has a number of sophisticated features which
make it by far the most user friendly A/C service system
in the world. The unit was designed for easy operation,
service and troubleshooting. Although the 3788X was
manufactured with high quality components, a compo-
nent failure could cause it to operate incorrectly.
The following section is designed to provide you with
additional information to help diagnose a system. If a
problem occurs, please read this section thoroughly
prior to calling technical support. This will reduce the
time needed to restore your system to normal operation.
Our technical support number is (800)769-8370.